What “Correct” Usually Means
When accountants talk about GST being correct, they usually mean the numbers add up. The GST on sales is calculated properly. The GST on purchases has been claimed according to tax invoices. The BAS report in Xero balances with the ledger.
On paper, that is correct GST.
If you search “GST correct but BAS audit risk” or “ATO GST review issues,” the concern isn’t usually arithmetic. It’s whether the reporting position can be explained clearly if questioned. That’s where defensibility comes in.
Correct GST focuses on calculation. Defensible GST focuses on explanation.
Where Defensibility Matters
A BAS can be technically accurate but still weak if the underlying coding decisions aren’t consistent or documented. For example, mixed-use expenses might have business-use percentages applied, but if those percentages change each quarter without documentation, the position becomes hard to defend.
Fuel tax credits might be claimed correctly in theory, but if there’s no record showing how eligibility was determined, that creates exposure. Director loan transactions might be coded properly now, but if earlier quarters treated them differently, patterns start to look inconsistent.
The ATO generally reviews trends and documentation, not just totals. If GST treatment changes across periods without clear reasoning, even correct numbers can raise questions.
The difference becomes clear during review. If someone asks why a GST amount was claimed, can you trace it back to a tax invoice, a calculation method, and a consistent process? If yes, it’s defensible. If not, it’s fragile.
The Takeaway
Correct GST means the numbers add up. Defensible GST means the numbers can be explained, supported, and repeated consistently over time.
When preparing BAS reports, focus not only on whether the GST figure is accurate today, but whether it would make sense to an external reviewer six months later. Clean transactions, consistent coding, and documented adjustments turn correct GST into defensible GST.
